These same receptors are found in humans, mice, and fish. And genes similar to the ones that encode the mouse receptors are also found in fish and humans, the researchers say, raising the possibility human noses are also equipped with pheromone receptors.

Sensors to Sense Sexual Cues?

The unique receptors are called trace amine-associated receptors (TAARs) and are different than the ones that sense odors in mice, the researchers, including Stephen Liberles, say.

However, like receptors that pick up scents, the mouse TAARs are programmed to detect particular compounds.

In their study, published in the journal Nature, the researchers identified three receptors that recognized three different compounds in mouse urine. This suggests they play a role in detecting subtle chemical messages between animals.

One of the compounds was linked to stressstress.

The other two were generally found in higher concentrations in male versus female urine. One of those two is thought to be a pheromone that provides sexual cues affecting readiness for mating.